KR20200043507A - Exhaust gas purification device - Google Patents

Abstract

An object of the present invention is to provide an exhaust gas purification device 1 having a structure in which exhaust gas can be uniformly introduced without depending on the shape of the exhaust gas inlet pipe 16. The gas purifying body 2 for purifying the exhaust gas, the purifying casing 60 accommodating the gas purifying body 2, and the exhaust gas inlet pipe 16 communicating with the exhaust gas inlet 12 of the purifying casing 60 ) And an exhaust gas outlet pipe 34 communicating with the exhaust gas outlet of the purification casing 60. The exhaust gas inlet pipe 16 is attached to the purification casing 60 so as to cover the exhaust gas inlet 12 and extend in the longitudinal direction of the purification casing 60. An exhaust gas introduction passage 200 is formed on the outer surface of the purification casing 60 and the inner surface of the pipe wall 201 of the exhaust gas inlet pipe 16. The portion 202 extending along the purifying casing 60 of the pipe wall 201 is inclined to approach the outer surface of the purifying casing 60 as it flows from the exhaust gas inlet side 16a toward the exhaust gas outlet side 16b. Order.

Description

Exhaust gas purification device {EXHAUST GAS PURIFICATION DEVICE}

The present invention relates to an exhaust gas purification device mounted on a diesel engine or the like, and more particularly, to an exhaust gas purification device that removes particulate matter (fumes, particles) contained in exhaust gas.

Conventionally, a diesel particulate filter (hereinafter referred to as DPF) is installed as an exhaust gas purification device in an exhaust path of a diesel engine (hereinafter referred to as an engine), and the exhaust gas from the diesel engine is purified by DPF. Technology is known (for example, see Patent Document 1). In DPF, a technique in which an inner case is provided in a double structure inside an outer case, and an oxidation catalyst or a soot filter or the like is incorporated in the inner case is also known (for example, see Patent Document 2).

Japanese Patent Publication 2004-263593 Japanese Patent Publication 2005-194949

However, the engine is widely used in a variety of fields, such as construction machinery, agricultural work machines. The mounting space of the engine varies depending on the machine to be mounted, but in recent years, the mounting space is often limited (narrow) due to the request for weight reduction and compactness. Moreover, in DPF, it is said that it is functionally preferable that the temperature of the exhaust gas passing through it is high temperature (for example, 300 ° C or more). For this reason, there is a request to attach the DPF to the engine.

When attaching the DPF to the engine, it is necessary to lengthen or curve the exhaust pipe connecting the exhaust manifold to the DPF depending on the DPF attachment position. However, the longer the exhaust pipe, the lower the exhaust gas temperature until it reaches the DPF, leading to a decrease in the exhaust gas purification performance of the DPF. Further, when the exhaust pipe passage is curved, the exhaust gas flows while colliding against the curved inner surface of the exhaust pipe, so the flow rate of the exhaust gas is naturally slowed down. Since the drop in the flow rate naturally urges a decrease in the exhaust gas temperature, this also leads to a decrease in the exhaust gas purification performance of the DPF.

Therefore, it is a technical problem of the present invention to provide a DPF having a structure in which exhaust gas can be uniformly introduced without considering the shape of the exhaust pipe after examining these current conditions.

The invention of claim 1 comprises a gas purifying body for purifying exhaust gas discharged by an engine, a purifying casing for accommodating the gas purifying body, an exhaust gas inlet pipe communicating with the exhaust gas inlet of the purifying casing, and the purifying casing. An exhaust gas outlet pipe communicating with the exhaust gas outlet, and covering the exhaust gas inlet and attaching the exhaust gas inlet pipe to the purification casing so as to extend in the longitudinal direction of the purification casing, and the outer surface of the purification casing. An exhaust gas purifying apparatus that forms an inlet passage for exhaust gas by an inner surface of a pipe wall of the exhaust gas inlet pipe, wherein a portion of the pipe wall of the exhaust gas inlet pipe extending along the purifying casing of the exhaust gas inlet pipe Outside of the purification casing as it goes from the exhaust gas inlet side toward the exhaust gas outlet side To access to the slope that was.

The invention of claim 2 is that in the exhaust gas purification device according to claim 1, a concave surface portion concave outward is formed on an inner surface side of a side end portion near the exhaust gas inlet in the purification casing.

The invention of claim 3 is the exhaust gas purification apparatus according to claim 1 or 2, wherein a portion of the pipe wall of the exhaust gas inlet pipe near the exhaust gas outlet is the exhaust gas outlet from the exhaust gas inlet side of the exhaust gas inlet pipe. It is said that it is inclined so as to be away from the center line on the inlet side of the exhaust gas as it moves toward the side.

(Effects of the Invention)

According to the invention of claim 1, a gas purifying body for purifying exhaust gas discharged by an engine, a purifying casing accommodating the gas purifying body, an exhaust gas inlet pipe communicating with the exhaust gas inlet of the purifying casing, and the purifying An exhaust gas outlet pipe communicating with the exhaust gas outlet of the casing is provided, and the exhaust gas inlet pipe is attached to the purification casing to cover the exhaust gas inlet and extend in the longitudinal direction of the purification casing. An exhaust gas purifying apparatus that forms an inlet passage for exhaust gas by a side surface and an inner surface of a pipe wall of the exhaust gas inlet pipe, wherein the portion of the pipe wall of the exhaust gas inlet pipe extending along the purifying casing is the exhaust gas inlet. The purifying casing as it goes from the exhaust gas inlet side of the tube to the exhaust gas outlet side Since it is inclined to approach the outer surface, the purification casing can be heated by the exhaust gas in the exhaust gas inlet pipe (in the introduction passage), thereby suppressing a decrease in the temperature of the exhaust gas passing through the purification casing. It becomes possible to do. Therefore, the exhaust gas purification performance of the exhaust gas purification device can be improved. The inclined shape of the portion of the tube wall extending along the purification casing may be a guide surface for transferring exhaust gas to the exhaust gas inlet. The exhaust gas inlet pipe can be used as a strength member of the purification casing, and the rigidity of the purification casing can be improved with a simple configuration without thickening the purification casing or increasing the number of parts extremely. While being able, the exhaust gas from the engine can be smoothly guided into the purification casing by the inclined shape of the portion of the tube wall extending along the purification casing. The exhaust gas can be supplied to a wide area of the gas purification body in the purification casing, contributing to the efficient utilization of the gas purification body.

According to the invention of claim 2, since the concave portion which is concave outward is formed on the inner surface side of the side end portion near the exhaust gas inlet in the purification casing, the concave portion from the exhaust gas inlet of the purification casing The exhaust gas can be supplied toward the surface, and swirling flow or turbulence can be easily formed on the exhaust gas upstream side of the gas purifying body by the exhaust gas diffusion action by the concave portion. For this reason, it is possible to supply the exhaust gas as evenly as possible to the end surface on the upstream side of the exhaust gas of the gas purification body.

According to the invention of claim 3, a portion of the pipe wall of the exhaust gas inlet pipe near the exhaust gas outlet port is located on the exhaust gas inlet side as it goes toward the exhaust gas outlet side from the exhaust gas inlet side of the exhaust gas inlet pipe. It is inclined away from the centerline. Although the exhaust gas collides with the outer surface of the purification casing in a portion of the inner wall of the pipe wall of the exhaust gas inlet pipe near the exhaust gas outlet, formation of swirling flow or turbulence is greater than that of the exhaust gas inlet because the volume of the portion is secured. It is also performed on the upstream side of the exhaust gas. The exhaust gas can be more evenly supplied to the end face on the upstream side of the exhaust gas of the gas purifying body.

1 is an explanatory cross-sectional view of a DPF.
2 is an external perspective view of the DPF.
3 is an external side view of the exhaust gas upstream side in the DPF.
4 is an external side view of the exhaust gas downstream of the DPF.
5 is an exploded cross-sectional view of the DPF.
6 is an exploded side view of the pinching flange.
7 is an enlarged side sectional view of the catalyst-side bonding flange.
8 is an enlarged cross-sectional view showing an attachment portion of the sensor boss body on the upstream side of the exhaust gas.
9 is an enlarged side sectional view of the exhaust gas upstream side in the DPF.
10 is a perspective view of a DPF-equipped diesel engine seen from the cooling fan side.
11 is a side view of the DPF-equipped diesel engine seen from the exhaust manifold side.
12 is a side view of the DPF-equipped diesel engine viewed from the flywheel side.

Hereinafter, the exhaust gas purification device embodying the present invention will be described based on the drawings. In the following description, the exhaust gas inlet 12 side in the diesel particulate filter 1 is referred to as the left side, and the silencer 30 side is similarly referred to as the right side. Terms indicating such a specific direction or position are used for convenience of description, and do not limit the technical scope of the present invention.

(1) Outline structure of the exhaust gas purification device

First, the schematic structure of the exhaust gas purification device will be described with reference to FIGS. 1 to 4. 1 to 4, a diesel particulate filter 1 of continuous regeneration type (hereinafter referred to as DPF 1) as an exhaust gas purification device is provided. The DPF 1 is configured to reduce carbon monoxide (CO) or hydrocarbon (HC) in the exhaust gas of the diesel engine 70 in addition to the removal of particulate matter (PM) in the exhaust gas of the diesel engine 70. Doing.

1 and 10 to 13, the DPF 1 as an exhaust gas purification device is for collecting particulate matter (PM) and the like in the exhaust gas, and the output shaft (crankshaft) of the diesel engine 70 and It is composed of a substantially cylindrical shape extending in a parallel left and right direction. The DPF 1 is disposed on the exhaust manifold 71 of the engine 70. The exhaust gas inlet pipe 16 and the exhaust gas outlet pipe 34 are provided on both the left and right sides of the DPF 1 (the upstream side and the downstream side in the direction in which the exhaust gas moves), which are divided into left and right sides of the diesel engine 70. The exhaust gas inlet pipe 16, which is the exhaust gas introduction side of the DPF 1, is bolted to the exhaust manifold 71 of the diesel engine 70 so as to be detachable. A tail pipe (not shown) is connected to the exhaust gas outlet pipe 34 which is the exhaust gas discharge side of the DPF 1.

As shown in Figs. 1 to 4, the DPF 1 is a diesel oxidation catalyst such as platinum, for example, through a cylindrical inner case 4, 20 in the DPF casing 60 as a purification casing made of a heat-resistant metal material. 2) and the honeycomb structured soot filter 3 are arranged in series and accommodated. 14 to 17, the DPF 1 includes a cylinder head 72 and an exhaust manifold of the diesel engine 70 through a flange-side bracket leg 61 and a casing-side bracket leg 62 as supports. 71).

In this case, the proximal end side of the flange side bracket leg 61 is bolted to the filter side joining flange 26 (detailed later) on the outer circumferential side of the DPF casing 60. In addition, the base end side of the casing side bracket leg 62 is bolted to the catalyst outer cover body 9 (detailed later) of the DPF casing 60 to be detachable. The front end side of the flange side bracket leg 61 is bolted detachably to the side surface of the cooling fan 76 side of the cylinder head 72. The front end side of the casing side bracket leg 62 is detachably bolted to the side surface of the flywheel housing 78 side of the cylinder head 72.

By fastening the inlet flange body 17 of the exhaust gas inlet pipe 16 (detailed later) to the outlet portion of the exhaust manifold 71, the exhaust manifold 71 is passed through the exhaust gas inlet pipe 16. The DPF 1 is connected in communication. As a result, the DPF 1 is stably connected to the exhaust manifold 71 and the cylinder head 72, which are high rigidity parts of the diesel engine 70, by the bracket legs 61 and 62, respectively. Therefore, it is possible to suppress damage to the DPF 1 due to vibration or the like.

In the above configuration, the exhaust gas of the diesel engine 70 flows from the exhaust manifold 71 of the diesel engine 70 to the side of the diesel oxidation catalyst 2 in the DPF casing 60, and from the diesel oxidation catalyst 2 It moves to the soot filter 3 side and is purified. Particulate matter in the exhaust gas cannot escape through the porous partition wall between each cell in the soot filter 3. That is, particulate matter in the exhaust gas is collected in the soot filter 3. Thereafter, the exhaust gas passing through the diesel oxidation catalyst 2 and the soot filter 3 is discharged from the tail pipe.

When the exhaust gas passes through the diesel oxidation catalyst 2 and the soot filter 3, if the temperature of the exhaust gas exceeds a renewable temperature (for example, about 300 ° C), the action of the diesel oxidation catalyst 2 Thereby, NO (nitrogen monoxide) in the exhaust gas is oxidized to unstable NO ₂ (nitrogen dioxide). Then, the particulate matter trapped in the soot filter 3 is oxidized and removed by O (oxygen) emitted when NO ₂ returns to NO. In addition, when particulate matter is deposited on the soot filter 3, when the exhaust gas temperature is maintained above the renewable temperature, the particulate matter is oxidized and removed, so that the collecting ability of the particulate matter of the soot filter 3 is restored [soot. The filter 3 is regenerated].

(2) Structure of diesel oxidation catalyst

Next, the structure of the diesel oxidation catalyst 2 which is an example of a gas purifying body (filter) for purifying exhaust gas discharged by the diesel engine 70 will be described with reference to FIGS. 1, 5, and 9. The diesel oxidation catalyst 2 is made of a heat-resistant metal material, and is provided in a substantially cylindrical catalyst inner case 4. The catalyst inner case 4 is made of a heat-resistant metal material and is provided in a substantially cylindrical catalyst outer case 5. That is, the catalyst inner case 4 is covered with a ceramic fiber outside the diesel oxidation catalyst 2 and through a mat-shaped catalyst insulating material 6. The catalyst insulating material 6 is press-fitted between the diesel oxidation catalyst 2 and the catalyst inner case 4 to protect the diesel oxidation catalyst 2. In addition, the catalyst outer case 5 is exposed on the outside of the catalyst inner case 4 through a thin plate-like support 7 having a cross section of approximately S shape. The catalyst outer case 5 is one of the elements constituting the DPF casing 60 described above. The stress (mechanical vibration or strain) of the catalyst outer case 5 transferred to the catalyst inner case 4 is reduced by the thin plate support 7.

As shown in Figs. 1, 5, and 9, a catalyst inner cover body 8 in a disk shape is fixed to one end of the catalyst inner case 4 and the catalyst outer case 5 by welding. On the outer surface side of the catalyst inner cover body 8, the catalyst outer cover body 9 is fastened by bolts and nuts. The gas inlet end surface 2a of the diesel oxidation catalyst 2 and the catalyst inner cover 8 are separated by a predetermined distance L1 (gas inlet space 11). An exhaust gas inflow space 11 is formed between the gas inlet side end surface 2a of the diesel oxidation catalyst 2 and the catalyst inner cover 8. In the catalyst inner case 4 and the catalyst outer case 5, the exhaust gas inlet 12 facing the exhaust gas inlet space 11 is opened. The opening edge of the exhaust gas inlet 12 in the catalyst outer case 5 is bent toward the catalyst inner case 4. Since the gap between the opening edge of the catalyst inner case 4 and the opening edge of the catalyst outer case 5 is closed by the bent edge, exhaust is provided between the catalyst inner case 4 and the catalyst outer case 5. Gas can be prevented from entering.

1, 5 and 9, the exhaust gas inlet pipe 16 is disposed on the outer surface of the catalyst outer case 5 in which the exhaust gas inlet 12 is formed. The exhaust gas inlet pipe 16 is formed in a half-half cylindrical shape that is opened upward, and a rectangular upward upward end 16b, which is a large diameter side, covers the exhaust gas inlet 12 and also has a length (left and right) of the catalyst outer case 5. It is extended in the direction and is fixed to the outer surface of the catalyst outer case 5 by welding. Therefore, the upward opening end portion 16b, which is the exhaust gas outlet side of the exhaust gas inlet pipe 16, is connected to the exhaust gas inlet 12 of the catalyst outer case 5 in communication. In the exhaust gas inlet pipe 16, a small-diameter round-shaped downward opening end 16a is opened as an exhaust gas inlet on the right end of the catalyst outer case 5 near the center of the length. The inlet flange body 17 is welded to the outer periphery of the downward opening end 16a. The inlet flange body 17 is detachably bolted to the exhaust gas discharge side of the exhaust manifold 71.

1, 5 and 9, the left end side of the exhaust gas inlet pipe 16 covers the exhaust gas inlet 12 of the catalyst outer case 5 from the outside. A downward opening end 16a as an exhaust gas inlet side is formed at the right end of the exhaust gas inlet pipe 16. That is, the downward opening end 16a of the exhaust gas inlet pipe 16 with respect to the exhaust gas inlet 12 is formed by offset to the exhaust gas downstream side of the DPF casing 60 (of the catalyst outer case 5). It is formed by shifting the position on the right side]. In addition, the upstream opening end 16b of the exhaust gas inlet pipe 16 covers the exhaust gas inlet 12 and also extends in the length (left and right) direction of the catalyst outer case 5 so that it is outside the catalyst outer case 5. Welded to the side. For this reason, the exhaust gas introduction passage 200 is formed by the outer surface of the catalyst outer case 5 and the inner surface of the pipe wall 201 of the exhaust gas inlet pipe 16. As a result, the DPF casing 60 (catalyst outer case 5) can be heated by the exhaust gas in the exhaust gas inlet pipe 16 (in the introduction passage 200), and the DPF casing 60 [catalyst It becomes possible to suppress the fall of the temperature of the exhaust gas passing through the inside of the outer case 5]. Therefore, the exhaust gas purification performance of the DPF 1 can be improved. In addition, the exhaust gas inlet pipe 16 can be used as a strength member of the DPF casing 60 (catalyst outer case 5), so that the DPF casing 60 (catalyst outer case 5) is thickened or the number of parts It is possible to improve the rigidity of the DPF casing 60 (catalyst outer case 5) with a simple configuration without increasing or increasing the temperature.

In the above configuration, the exhaust gas of the diesel engine 70 enters the exhaust gas inlet pipe 16 from the exhaust manifold 71, and the exhaust gas flows in through the exhaust gas inlet 12 from the exhaust gas inlet pipe 16 It enters the space 11, and is supplied to the diesel oxidation catalyst 2 from the gas inlet side end surface 2a on the left side. Nitrogen dioxide (NO ₂ ) is produced by the oxidation action of the diesel oxidation catalyst 2.

As shown in FIGS. 1, 5, and 9, a portion of the pipe wall 201 of the exhaust gas inlet pipe 16 extending along the DPF casing 60 (catalyst outer case 5) is an exhaust gas inlet pipe On the outer surface of the DPF casing 60 (catalyst outer case 5) from the exhaust gas inlet side 16 (downward opening end 16a) toward the exhaust gas outlet side (upward opening end 16b). It is formed in the inclined portion 202 inclined to approach. In other words, the portion extending along the DPF casing 60 (catalyst outer case 5) of the tube wall 201 is a length inclined portion 202 shaped like an angled corner when viewed from the side. The inner surface of the length inclined portion 202 of the exhaust gas inlet pipe 16 is covered with the exhaust gas inlet 12 of the DPF casing 60 (catalyst outer case 5), and flows from the exhaust manifold 71 The exhaust gas is configured to drift in the direction of the exhaust gas inlet 12.

In the above configuration, the exhaust gas flowing into the exhaust gas inlet pipe 16 from the exhaust manifold 71 collides against the inner surface of the length inclined portion 202 of the exhaust gas inlet pipe 16, and the exhaust gas inlet 12 ), And is smoothly guided into the exhaust gas inlet space 11 via the exhaust gas inlet 12. That is, the inner surface of the length inclined portion 202 of the exhaust gas inlet pipe 16 is used as a guide surface for transferring the exhaust gas to the exhaust gas inlet 12, and the exhaust gas inlet pipe 16 is a DPF casing 60 It can be used as a strength member of [catalyst outer case 5], DPF casing 60 in a simple configuration without thickening the DPF casing 60 [catalyst outer case 5] or increasing the number of parts extremely. While being able to improve the rigidity of the [catalyst outer case 5], the exhaust gas from the exhaust manifold 71 is DPFed by the inner surface of the length inclined portion 202 of the exhaust gas inlet pipe 16. It can be guided smoothly into the casing 60 (catalyst outer case 5). Therefore, exhaust gas can be supplied to a wide area of the diesel oxidation catalyst 2, which is a gas purifier in the DPF casing 60 (catalyst outer case 5), contributing to the efficient utilization of the diesel oxidation catalyst 2.

1, 5, and 9, a portion of the pipe wall 201 of the exhaust gas inlet pipe 16 near the exhaust gas outlet pipe 34 which is also an exhaust gas outlet is an exhaust gas inlet pipe 16 Center line C of the exhaust gas inlet side (downward opening end 16a) from the exhaust gas inlet side (downward opening end 16a) toward the exhaust gas outlet side (upward opening end 16b) (FIG. 1) And (see FIG. 9). In other words, about half of the pipe wall 201 near the exhaust gas outlet pipe 34 is a trumpet-shaped width inclined portion 203 whose radius widens from the downwardly opening end 16a toward the upwardly opening end 16b. have. In this case, in the portion near the exhaust gas outlet pipe 34 among the inner surfaces of the pipe wall 201 of the exhaust gas inlet pipe 16, the exhaust gas collides with the outer surface of the DPF casing 60 (catalyst outer case 5). However, since the volume of the portion is secured, the formation of swirling flows and turbulence is also performed on the exhaust gas upstream side of the exhaust gas inlet 12. Therefore, the exhaust gas can be more evenly supplied to the end surface 2a (gas inlet end surface 2a) of the exhaust gas upstream side of the diesel oxidation catalyst 2 more reliably.

1, 5 and 9, the inner surface side of the catalyst inner cover body 8 among the side end portions near the exhaust gas inlet 12 in the DPF casing 60 (catalyst outer case 5) A concave surface portion 204 that is concave outward is formed. Therefore, the catalyst inner cover body 8 has a rice air shape in which the central portion of the inner surface side is most concave by the presence of the concave portion 204. For this reason, exhaust gas can be supplied from the exhaust gas inlet 12 of the DPF casing 60 (catalyst outer case 5) toward the concave portion 204 of the catalyst inner cover body 8, and the concave portion 204 By the exhaust gas diffusion action by), swirl flow or turbulence can be easily formed on the exhaust gas upstream side (exhaust gas inflow space 11) of the diesel oxidation catalyst 2. For this reason, the exhaust gas can be supplied as uniformly as possible to the end surface (gas inlet side end surface 2a) of the exhaust gas upstream side of the diesel oxidation catalyst 2.

(3) Structure of soot filter

Next, with reference to FIGS. 1, 5 and 9, the structure of the soot filter 3 which is an example of a gas purifying body (filter) for purifying the exhaust gas discharged by the diesel engine 70 will be described. The soot filter 3 is made of a heat-resistant metal material and is installed in the filter inner case 20 of a substantially cylindrical shape. The filter inner case 20 is made of a heat-resistant metal material, and is installed in the filter outer case 21 of a substantially cylindrical shape. That is, the filter inner case 20 is exposed through the filter-shaped insulating material 22 made of ceramic fiber on the outside of the soot filter 3. The filter outer case 21 is one of elements constituting the DPF casing 60 described above together with the catalyst outer case 5. In addition, the filter insulating material 22 is pressed between the soot filter 3 and the filter inner case 20 to protect the soot filter 3.

As shown in Figs. 1, 5, and 9, the catalyst inner case 4 in which the ridgeline is formed in a straight cylindrical shape includes an upstream cylinder portion 4a accommodating the diesel oxidation catalyst 2, and a filter inner case described later. It is comprised by the downstream side cylinder part 4b into which 20 is inserted. Moreover, the upstream-side cylinder part 4a and the downstream-side cylinder part 4b are cylinders of substantially the same diameter, and are integrally formed. In addition, a thin ring-shaped catalyst side bonding flange 25 welded and fixed to the outer circumference of the catalyst inner case 4 and a thin ring-shaped filter side bonding flange 26 welded and fixed to the outer circumference of the filter inner case 20 It is provided. The catalyst-side joining flange 25 and the filter-side joining flange 26 are formed in a substantially L-shaped donut cross section.

The inner circumferential side of the catalyst side joining flange 25 is welded and fixed to the end portion of the downstream side cylinder portion 4b in the catalyst inner case 4. The outer circumferential side of the catalyst-side bonding flange 25 is projected toward the outer circumferential side (radiation direction) of the catalyst outer case 5. The bent corner portion of the catalyst-side bonding flange 25 is a step-shaped stepped portion 25a. The end portion on the downstream side of the exhaust gas in the catalyst outer case 5 is welded and fixed to the stepped portion 25a of the catalyst side joining flange 25. On the other hand, the inner circumferential side of the filter side joining flange 26 is welded and fixed to the length middle portion (middle portion in the exhaust gas movement direction) of the outer circumference of the filter inner case 20. The outer circumferential side of the filter side joining flange 26 is projected toward the outer circumferential side (radiation direction) of the filter outer case 21. The bent corner portion of the filter side joining flange 26 is also a stepped portion 26a. In the filter outer case 21, the end portion on the upstream side of the exhaust gas is welded and fixed to the step portion 26a of the filter side joining flange 26. In addition, the filter inner case 20 has a ridgeline formed in a straight cylindrical shape. The end portion on the upstream side of the exhaust gas and the end portion on the downstream side of the exhaust gas of the filter inner case 20 are cylindrical with substantially the same diameter, and are integrally formed.

The outer diameter of the diesel oxidation catalyst 2 and the outer diameter of the soot filter 3 are formed identically. The thickness of the catalytic insulating material 6 is made larger than the thickness of the filter insulating material 22. On the other hand, the catalyst inner case 4 and the filter inner case 20 are formed of a material having the same plate thickness. The outer diameter of the filter inner case 20 is formed smaller than the inner diameter of the downstream cylinder 4b of the catalyst inner case 4. A downstream gap 23 is formed between the inner circumferential surface of the catalyst inner case 4 and the outer circumferential surface of the filter inner case 20. The downstream gap 23 is formed with a dimension (for example, 2 millimeters) larger than the plate thickness (for example, 1.5 millimeters) of each case 4 and 20. When configured in this way, for example, even if the cases 4 and 20 are rusted or thermally deformed, the end portion on the exhaust gas upstream side of the filter inner case 20 is placed in the downstream cylinder 4b of the catalyst inner case 4 even if the case 4 is rusted or thermally deformed. It becomes possible to simply deposit and withdraw.

1 to 5 and 8, the catalyst-side bonding flange 25 and the filter-side bonding flange 26 are fitted through the gasket 24. Each of the joining flanges 25 and 26 is sandwiched from both sides in the direction of exhaust gas movement by a pair of thick plate-like central clamping flanges 51 and 52 surrounding the outer circumferential sides of the outer cases 5 and 21. The outer casing of the catalyst is secured by fastening each of the central clamping flanges 51 and 52 with the bolts 27 and the nuts 28 and clamping the bonding flanges 25 and 26 with the central clamping flanges 51 and 52. 5) and the filter outer case 21 are detachably connected.

1 and 8, the filter outer case 21 is disposed at the end portion on the exhaust gas downstream side of the catalyst outer case 5 through each of the central clamping flanges 51 and 52 and each of the joining flanges 25 and 26. In the state where the ends of the exhaust gas upstream side are connected, a space 29 on the catalyst downstream side is formed between the diesel oxidation catalyst 2 and the soot filter 3. That is, the gas outlet side end face 2b of the diesel oxidation catalyst 2 and the introduction side end face 3a of the soot filter 3 (filter inner case 20) are replaced by a distance L2 for attaching the sensor. .

1 and 5, the cylinder in the exhaust gas movement direction of the catalyst outer case 5 is larger than the cylinder length L3 in the exhaust gas movement direction of the upstream cylinder 4a in the catalyst inner case 4 The length L4 is formed long. The cylinder length L6 of the filter outer case 21 in the exhaust gas movement direction is shorter than the cylinder length L5 of the filter inner case 20 in the exhaust gas movement direction. The interval (L2) for attaching the sensor in the space 29 on the catalyst downstream side, the cylinder length L3 of the upstream cylinder portion 4a of the catalyst inner case 4, and the cylinder length L5 of the filter inner case 20 are The added length (L2 + L3 + L5) is substantially equal to the added length (L4 + L6) of the cylinder length (L4) of the catalyst outer case (5) and the cylinder length (L6) of the filter outer case (21). Consists of.

In addition, the end of the filter inner case 20 on the upstream side of the exhaust gas projects from the end of the filter outer case 21 on the side of the exhaust gas upstream by the difference L7 ≒ L5-L6 of the length of each case 20, 21. It is done. For this reason, in the state in which the filter outer case 21 is connected to the catalyst outer case 5, the catalyst outer case (L7) up to the exhaust gas upstream side dimension L7 of the filter inner case 20 protruding from the filter outer case 21 The end portion of the exhaust gas upstream side of the filter inner case 20 is inserted into the exhaust gas downstream side of 5) (the downstream side cylinder portion 4b of the catalyst inner case 4). That is, the exhaust gas upstream side of the filter inner case 20 is inserted / removably inserted into the downstream side cylinder 4b (catalyst downstream side space 29). As can be seen from the above description and Fig. 1, for the connection boundary position (catalytic downstream side space 29) of the diesel oxidation catalyst 2 and the soot filter 3, the catalyst outer case 5 and the filter outer case The flange body (catalyst side joining flange 25 and filter side joining flange 26) connecting (21) is offset. In other words, the attachment positions of the catalyst-side bonding flange 25 and the filter-side bonding flange 26 are shifted with respect to the catalyst downstream-side space 29.

In the above configuration, nitrogen dioxide (NO ₂ ) produced by the oxidation action of the diesel oxidation catalyst 2 is supplied from one end surface (introduction side end surface 3a) into the soot filter 3. Particulate matter (PM) contained in the exhaust gas of the diesel engine 70 is collected by the soot filter 3 and continuously oxidized and removed by nitrogen dioxide (NO ₂ ). In addition to the removal of particulate matter (PM) in the exhaust gas of the diesel engine 70, the content of carbon monoxide (CO) or hydrocarbon (HC) in the exhaust gas of the diesel engine 70 is reduced.

(4) Structure of the silencer

Next, with reference to FIGS. 1 and 5, the structure of the silencer 30 to attenuate the exhaust gas sound emitted by the diesel engine 70 will be described. 1 and 5, the silencer 30 that attenuates the exhaust gas sound emitted by the diesel engine 70 is made of a heat-resistant metal material, and is made of a substantially cylindrical noise inner case 31 and a heat-resistant metal material. It has a substantially cylindrical noise outer case 32 and a disk-shaped noise outer cover body 33 fixed by welding to a side end of the noise outer case 32 on the downstream side of the exhaust gas. The noise inner case 31 is installed in the noise outer case 32. The noise outer case 32 together with the catalyst outer case 5 and the filter outer case 21 constitutes the DPF casing 60 described above. Further, the diameter of the cylindrical noise outer case 32 is approximately the same as the diameter of the cylindrical catalyst outer case 5 or the diameter of the cylindrical filter outer case 21.

In the noise inner case 31, a disc-shaped noise-proof cover body 36 is fixed to the end portion on the upstream side of the exhaust gas by welding. In the noise inner case 31, a pair of exhaust gas introduction pipes 38 extending in parallel with the direction in which the exhaust gas moves are provided. The exhaust gas upstream side of each exhaust gas introduction pipe 38 passes through the noise-proof cover body 36, but the end portion of the exhaust gas upstream side of each exhaust gas introduction pipe 38 and the exhaust gas of the noise inner case 31 The positions of the upstream end portions are almost identical when viewed in the side section. The end portion on the upstream side of the exhaust gas in each exhaust gas introduction pipe 38 is opened as it is. A plurality of communication holes 39 are formed in each exhaust gas introduction pipe 38. Each exhaust gas introduction pipe 38 communicates with the expansion chamber 45 through the communication hole 39. The expansion chamber 45 is formed inside the noise inner case 31 (between the noise inner cover body 36 and the noise outer cover body 33).

The noise outer cover body 33 of the noise outer case 32 is passed through the exhaust gas outlet pipe 34 disposed between each exhaust gas introduction pipe 38. The exhaust gas upstream side of the exhaust gas outlet pipe 34 is closed by a noise inner cover body 36. A number of exhaust holes 46 are formed in the exhaust gas outlet pipe 34 in the noise inside case 31. Each exhaust gas introduction pipe 38 communicates with the exhaust gas outlet pipe 34 through a plurality of communication holes 39, an expansion chamber 45, and a plurality of exhaust holes 46. A tail pipe (not shown) is connected to the other end side of the exhaust gas outlet pipe 34. In the above configuration, the exhaust gas that has entered into both exhaust gas introduction pipes 38 of the noise inner case 31 passes through a plurality of communication holes 39, an expansion chamber 45, and a plurality of exhaust holes 46. It passes through the outlet pipe 34 and is discharged out of the silencer 30 through the tail pipe.

1 and 5, the inner diameter side of the thin ring-shaped filter outlet side joining flange 40 is welded and fixed to the downstream end portion of the filter inner case 20 on the exhaust gas side. The outer diameter side of the filter outlet side joining flange 40 is projected toward the outer circumferential side (radius outer side, radial direction) of the filter outer case 21. The end of the filter outer case 21 downstream of the exhaust gas is welded and fixed to the outer circumferential side of the filter outlet side joining flange 40. A thin plate-shaped noise side joining flange 41 protruding to the outer circumferential side (radius outer side) of the noise outer case 32 is welded and fixed to an end portion on the exhaust gas upstream side of the noise inner case 31. An end portion on the upstream side of the exhaust gas of the noise outer case 32 is welded and fixed to the outer circumferential side of the noise side joining flange 41. Further, an end portion on the upstream side of the exhaust gas of the noise inner case 31 is protruded by a predetermined cylinder dimension L10 on the upstream side of the exhaust gas on the noise side joining flange 41. In addition, the filter inner case 20 and the noise inner case 31 are cylinders of approximately the same diameter, and the filter outer case 21 and the noise outer case 32 are cylinders of approximately the same diameter.

1 to 4 and 6, the filter outlet side joining flange 40 and the noise side joining flange 41 are fitted through the gasket 24, and the outer circumferential side of each outer case 21, 32 is shown. Each joining flange 40, 41 is clamped from both sides in the exhaust gas movement direction by a pair of enclosing outlet plate-shaped flanges 53, 54. In addition, the filter outer case 21 and the noise outer case 32 can be detached by fastening the respective outlet flanges 53 and 54 to the respective joining flanges 40 and 41 by the bolts 42 and the nuts 43. Is connected.

1 and 5, the cylinder length L9 in the exhaust gas movement direction of the noise outer case 32 is shorter than the cylinder length L8 in the exhaust gas movement direction of the noise inner case 31. . The end of the noise inner case 31 on the exhaust gas upstream side is the difference between the length of each case 31, 32 (L10_L8) from the end of the noise outer case 32 on the exhaust gas upstream side (joint flange 41). -L9). That is, in the state where the noise outer case 32 is connected to the filter outer case 21, the exhaust gas of the filter outer case 21 is equal to the dimension L10 in which the end portion on the exhaust gas upstream side of the noise inner case 31 protrudes. The exhaust gas upstream end of the noise inner case 31 is inserted into the filter downstream space 49 formed in the downstream end (filter outlet side joining flange 40). As can be seen from the above description and Fig. 1, a flange body connecting the filter outer case 21 and the noise outer case 32 with respect to the connection boundary position (filter downstream side space 49) of the soot filter 3 [The filter outlet side joining flange 40 and the noise side joining flange 41] are offset. In other words, the attachment positions of the filter outlet side joining flange 40 and the noise side joining flange 41 are shifted with respect to the filter downstream side space 49.

When configured as described above, it is possible to shorten the length of the exhaust gas movement direction of the silencer 30 (noise outer case 32) while securing the length of the exhaust gas introduction pipe 38 in the exhaust gas movement direction. . Therefore, in the DPF 1 to which the silencer 30 is attached, both the compaction as the whole DPF 1 and the maintenance improvement of the noise function in the silencer 30 can be achieved.

(5) Connection structure between neighboring outer cases

Next, a connection structure between neighboring outer cases 5, 21 and 32 will be described with reference to Figs. 1 to 4 and Fig. 6. As shown in Figs. 1 to 4 and Fig. 6, a plurality of plate-shaped central pinching flanges 51 (52) in the circumferential direction of the catalyst outer case 5 (filter outer case 21) (2 in the embodiment) It consists of semicircular arc bodies (51a, 51b (52a, 52b)) divided into pieces. Each semicircular arc body 51a, 51b (52a, 52b) of the embodiment is formed in an arc shape (almost semicircular horseshoe shape). In the state where the filter outer case 21 is connected to the catalyst outer case 5, the ends of each semicircular arc bodies 51a, 51b (52a, 52b) are butted (contact) in the circumferential direction. That is, the outer circumferential side of the catalyst outer case 5 (filter outer case 21) is enclosed in an annular shape by each semicircular arc body 51a, 51b (52a, 52b).

A plurality of bolt fastening portions 55 to which through holes are attached at equal intervals along the circumferential direction are provided in the central pinching flange 51 (52). In the embodiment, ten bolt fastening portions 55 are provided for one set of central clamping flanges 51. Viewed from each semicircular arc body 51a, 51b (52a, 52b) unit, bolt fastening portions 55 are provided at equal intervals along the circumferential direction. On the other hand, a bolt hole 56 corresponding to each bolt fastening portion 55 of the central clamping flange 51 (52) is formed through the catalyst-side bonding flange 25 and the filter-side bonding flange 26.

When the catalyst outer case 5 and the filter outer case 21 are connected, the outer circumferential side of the catalyst outer case 5 is surrounded by both semicircular arc bodies 51a, 51b on the catalyst side, and the filter outer case 21 The catalytic side joining flange 25 and the filter side joining flange 26 that surround the outer circumferential side with both semicircular arc bodies 52a and 52b on the filter side, and the gasket 24 are sandwiched by these semicircular body groups (central engagement flange 51 , 52)]. Subsequently, the bolts 27 are inserted into the bolt fastening portions 55 of the center clamping flanges 51 and 52 on both sides, and the bolt holes 56 of both the joining flanges 25 and 26, and fastened with the nuts 28. . As a result, both joining flanges 25 and 26 are fitted and fixed by both center pinching flanges 51 and 52, and the connection between the catalyst outer case 5 and the filter outer case 21 is completed. Here, the abutting portions of the ends of the semicircular arc bodies 51a and 51b on the catalyst side and the semicircular arc bodies 52a and 52b on the filter side are configured to be positioned with the 72 ° phase shifted from each other.

As shown in Figs. 1 to 4, a plurality of (two in the embodiment) circumferential directions of the filter outer case 21 (noise outer case 32) of the plate-shaped outlet pinching flanges 53 (54) are provided. It is composed of divided semicircular arc bodies (53a, 53b (54a, 54b)). Each semicircular body [53a, 53b (54a, 54b)] of the embodiment is basically the same shape as the semicircular body [51a, 51b (52a, 52b)] of the central pinching flange [51 (52)]. The outlet clamping flange 53 (54) is also provided with a plurality of bolt fastening portions 57 having through holes attached at equal intervals along the circumferential direction. On the other hand, a bolt hole 58 corresponding to each bolt fastening portion 57 of the outlet clamping flange 53 (54) is formed through the filter outlet side joining flange 40 and the noise side joining flange 41.

When connecting the filter outer case 21 and the noise outer case 32, the outer circumferential side of the filter outer case 21 is surrounded by both semicircular arc bodies 53a, 53b on the filter outlet side, and the noise outer case 32 The filter outlet side joining flange 40 and the noise side joining flange 41 that surround the outer circumferential side of the noise side with both semicircular arc bodies 54a and 54b, and sandwich the gasket 24, are located in these semicircular body groups (outlet clamping flange (53, 54)] from both sides of the exhaust gas movement direction. Subsequently, the bolts 42 are inserted into the bolt fastening portions 57 of the outlet clamping flanges 53 and 54 on both sides and the bolt holes 58 of both the joining flanges 40 and 41 to fasten the nuts 43. . As a result, both joining flanges 40 and 41 are fitted and fixed by both outlet pinching flanges 53 and 54, and the connection between the filter outer case 21 and the noise outer case 32 is completed. Here, the abutting portions of the ends of the semicircular arc bodies 53a, 53b on the filter outlet side and the semicircular arc bodies 54a, 54b on the noise side are configured to be positioned with the 72 ° phase shifted from each other.

1 to 4 and 6, the gas purifying bodies 2 and 3 for purifying the exhaust gas emitted by the engine 70, and each inner case incorporating the respective gas purifying bodies 2 and 3 (4, 20, 31) and each outer case (5, 21, 32) incorporating each inner case (4, 20, 31) are provided. Each inner case (4, 20, 31) is attached to each outer case (5, 21, 32) through a joining flange (25, 26, 40, 41) protruding to the outer circumferential side of each outer case (5, 21, 32). Connect. A plurality of combinations of gas purifying bodies 2, 3, each inner case 4, 20, 31 and each outer case 5, 21, 32 are provided, and each joining flange [25, 26 (40, 41)] Is clamped by a pair of pinching flanges 51, 52 (53, 54) to connect the plurality of outer cases 5, 21, 32.

With this configuration, the adjacent joining flanges 25, 26 (40, 41) can be fitted and pressed (bonded) from both sides by the respective gripping flanges 51, 52 (53, 54). Further, since the clamping flanges 51 to 54 are separately formed without welding to the outer cases 5, 21, and 32, welding is performed in the relationship between the clamping flanges 51 to 54 and the outer cases 5, 21, and 32. There is no fear of stress concentration and deformation problems caused by. For this reason, it is possible to impart a substantially uniform pressing force to the entirety of each of the joining flanges 25, 26 (40, 41), and to increase the surface pressure of the sealing surfaces (engaged surfaces) of the gripping flanges 51-54. You can keep it. As a result, it is possible to reliably prevent leakage of exhaust gas from between the respective joining flanges 25, 26 (40, 41).

1 to 4 and 6, each of the pinching flanges 51 to 54 is a horseshoe-shaped semicircular arc body 51a, 51b (52a) divided into a plurality in the circumferential direction of the outer casings 5, 21, 32 , 52b, 53a, 53b, 54a, 54b)], and the outer casings 5, 21, 32 of a plurality of semicircular arcs [51a, 51b (52a, 52b, 53a, 53b, 54a, 54b)]. It is configured to surround the outer periphery. Therefore, it is possible to make the mounting state similar to that of the integral body while being the pinching flanges 51 to 54 composed of a plurality of semicircular arc bodies 51a, 51b (52a, 52b, 53a, 53b, 54a, 54b). For this reason, mounting of the pinching flanges 51 to 54 is easier than that of the ring-shaped flange, and the mounting workability can be improved. Moreover, the DPF 1 with high sealing property can be comprised, suppressing a processing cost and a mounting cost.

(6) Detailed structure of joint flange

Next, the detailed structure of each joining flange 25, 26, 40 is demonstrated. Since each of the joining flanges 25, 26, and 40 are basically the same structure, the catalyst side joining flange 25 welded to the catalyst inner case 4 and the catalyst outer case 5 as representative examples is shown in FIG. 7. This is explained with reference to. As shown in Fig. 7, a stepped stepped portion 25a is formed at the bent corner portion of the catalyst-side bonding flange 25. The stepped portion 25a is covered with the end of the catalyst outer case 5 on the downstream side of the exhaust gas, and the stepped portion 25a is welded and fixed to the end of the catalyst outer case 5 on the downstream side.

On the other hand, the L-shaped inner diameter side end portion 25b in the catalyst side joining flange 25 is spoken in the direction in which the catalyst inner case 4 (catalyst outer case 5) moves in the exhaust gas. The inner diameter side end portion 25b is covered with the end portion on the downstream side of the exhaust gas side of the catalyst inner case 4, and the inner diameter side end portion 25b is welded and fixed to the catalyst inner case 4. On the other hand, from the outer periphery of the catalyst outer case 5, the L-shaped outer diameter side end portion 25c of the catalyst side joining flange 25 is spoken from the outer circumferential direction (vertical direction). High rigidity of the catalyst-side bonding flange 25 is ensured by the cross-sectional L-shape of the catalyst-side bonding flange 25 and the presence of the step portion 25a.

In addition, the nut 28 is screwed to the bolt 27 through each bolt hole 56 of the clamping flanges 51 and 52 and the joining flanges 25 and 26, thereby allowing the clamping flanges 51 and 52 and the joining flange. The structures in which (25, 26) are fastened and the outer diameter side end portion 25c of the catalyst side bonding flange 25 is clamped by the clamping flanges 51 and 52 are as described above.

(6) Gas temperature sensor attachment structure

Next, gas temperature sensors 109 and 112 attached to the DPF 1 will be described with reference to FIGS. 1, 8, and 9. 1, 8 and 9, one end of the cylindrical sensor boss body 110 is welded between the upstream side cylinder portion 4a and the downstream side cylinder portion 4b of the outer circumferential surface of the catalyst inner case 4 It is fixed. The other end of the sensor boss body 110 is extended in the radial direction from the sensor-attached opening 5a of the catalyst outer case 5 toward the outside of the catalyst outer case 5. That is, the sensor boss body 110 for supporting the exhaust gas sensor in the vicinity of the connection boundary position (the catalyst downstream side space 29) of the diesel oxidation catalyst 2 and the soot filter 3 on the outer circumferential surface of the catalyst inner case 4 ) Is provided to penetrate the catalyst outer case (5). The sensor attachment bolt 111 is screwed to the other end of the sensor boss body 110. For example, the thermistor type upstream gas temperature sensor 109 is passed through the sensor attachment bolt 111, and the upstream gas temperature sensor 109 is passed through the sensor attachment bolt 111 to the sensor boss body 110. Support. The detection portion of the upstream gas temperature sensor 109 is inserted into the catalyst downstream side space 29. In the above configuration, when the exhaust gas is discharged from the gas outlet side end surface 2b of the diesel oxidation catalyst 2, the exhaust gas temperature is detected by the upstream gas temperature sensor 109.

8 and 9, the sensor boss body 110 on the exhaust gas upstream side is an extended phase of the gas outlet side end surface 2b orthogonal to the exhaust gas movement direction in the diesel oxidation catalyst 2, and In the soot filter 3, it is located on the extension of the inlet side end face 3a orthogonal to the exhaust gas movement direction. In this case, the arrangement interval between the gas outlet side end face 2b of the diesel oxidation catalyst 2 and the introduction side end face 3a of the soot filter 3 and the upstream side gas temperature sensor 109 is set very short (proximity) Since it becomes possible to achieve the compactness of the entire DPF 1, it is possible to improve the detection accuracy of the upstream gas temperature sensor 109, and performance such as regeneration control for the DPF 1 Contribute to improvement.

1 and 5, one end of the cylindrical sensor boss body 110 is fixed to the vicinity of the filter downstream side space 49 of the outer circumferential surface of the filter inner case 20. The other end of the sensor boss body 110 is extended in the radial direction from the sensor opening 21a of the filter outer case 21 toward the outside of the filter outer case 21. That is, the sensor boss body 110 for supporting the exhaust gas sensor is provided to penetrate the filter outer case 21 in the vicinity of the connection boundary position of the soot filter 3 on the outer circumferential surface of the filter inner case 20. The sensor attachment bolt 111 is screwed to the other end of the sensor boss body 110. For example, the thermistor-type downstream gas temperature sensor 112 is passed through the sensor attachment bolt 111, and the downstream gas temperature sensor 112 is passed through the sensor attachment bolt 111 to the sensor boss body 110. Support. The detection portion of the downstream gas temperature sensor 112 is inserted into the filter downstream side space 49. In the above configuration, when exhaust gas is discharged from the exhaust-side end face 3b of the soot filter 3, the exhaust gas temperature is detected by the downstream gas temperature sensor 112. In addition, although not shown in detail, it goes without saying that the sensor boss body of the differential pressure sensor can be configured similarly to the sensor boss body 110 for both gas temperature sensors 109 and 112.

(7) Theorem

As clearly indicated from the above description and FIGS. 1, 5 and 9, a gas purifying body 2 for purifying the exhaust gas emitted by the engine 70 and a purifying casing accommodating the gas purifying body 2 60, an exhaust gas inlet pipe 16 communicating with the exhaust gas inlet 12 of the purification casing 60, and an exhaust gas outlet pipe 34 communicating with the exhaust gas outlet of the purification casing 60 It is provided, and the exhaust gas inlet tube 12 is also attached to the exhaust gas inlet pipe 16 to the purification casing 60 so as to extend in the longitudinal direction of the purification casing 60, and the purification casing 60 ) In the exhaust gas purifying device (1) forming an inlet passage 200 for exhaust gas by an outer surface of the exhaust gas inlet pipe (16) and an inner surface of the pipe wall (201) of the exhaust gas inlet pipe (16), The portion 202 of the tube wall 201 of 16) extending along the purification casing 60 Since the exhaust gas inlet pipe 16 is inclined to approach the outer surface of the purification casing 60 from the exhaust gas inlet side 16a toward the exhaust gas outlet side 16b, the exhaust gas inlet pipe (16) The purification casing 60 can be heated by the exhaust gas in the inside (in the introduction passage 200), and it is possible to suppress a decrease in the temperature of the exhaust gas passing through the purification casing 60. Becomes Therefore, the exhaust gas purification performance of the exhaust gas purification device 1 can be improved. The inclined shape of the portion 202 extending along the purification casing 60 of the pipe wall 201 serves as a guide surface for transferring the exhaust gas to the exhaust gas inlet 12. The exhaust gas inlet pipe 16 can be used as a strength member of the purification casing 60, so that the purification casing 60 has a simple configuration without thickening the purification casing 60 or dramatically increasing the number of parts. ), While purifying the exhaust gas from the engine 70 by the inclined shape of the portion 202 extending along the purifying casing 60 among the pipe walls 201. (60) You can guide me smoothly. The exhaust gas can be supplied to a wide area of the gas purifying body 2 in the purifying casing 60, contributing to the efficient utilization of the gas purifying body 2.

As clearly indicated from the above description and FIGS. 1, 5, and 9, the inner side of the side end portion 8 near the exhaust gas inlet 12 in the purification casing 60 becomes concave outward. Since the concave portion 204 is formed, exhaust gas can be supplied from the exhaust gas inlet 12 of the purification casing 60 toward the concave portion 204, and exhaust by the concave portion 204 By the gas diffusion action, swirl flow or turbulence can be easily formed on the exhaust gas upstream side of the gas purifying body 2. For this reason, the exhaust gas can be supplied as evenly as possible to the end face 2a on the upstream side of the exhaust gas of the gas purification body 2.

As clearly indicated from the above description and FIGS. 1, 5 and 9, a portion 203 of the pipe wall 201 of the exhaust gas inlet pipe 16 near the exhaust gas outlet 34 is the exhaust gas inlet. The pipe 16 is inclined to be separated from the center line C of the exhaust gas inlet side 16a from the exhaust gas inlet side 16a toward the exhaust gas outlet side 16b. In the portion 203 near the exhaust gas outlet 34 of the inner surface of the pipe wall 201 of the exhaust gas inlet pipe 16, the exhaust gas collides with the outer surface of the purification casing 60, but the portion 203 Since the volume of) is secured, the formation of swirling flows and turbulence is also performed on the exhaust gas upstream side of the exhaust gas inlet 12. The exhaust gas can be more evenly supplied to the end surface 2a on the upstream side of the exhaust gas of the gas purifying body 2 more reliably.

In addition, the structure of each part in the present invention is not limited to the illustrated embodiment, and various modifications can be made without departing from the spirit of the present invention.

1: DPF (Diesel Particulate Filter) 2: Diesel oxidation catalyst (gas purifier)
3: Soot filter (gas purification body) 4: Catalyst inner case
5: catalyst outer case 20: filter inner case
21: filter outer case
25, 26, 40, 41: joint flange (flange body)
30: silencer 31: noise inner case
32: noise outer case 38: exhaust gas introduction pipe
60: DPF casing 70: diesel engine
200: introduction passage 201: pipe wall
202: length slope 203: width slope
204: concave surface portion

Claims (5)

In the exhaust gas purification apparatus having a casing and an exhaust gas inlet pipe communicating with the exhaust gas inlet of the casing,
The exhaust gas purifying apparatus characterized in that the pipe wall of the exhaust gas inlet pipe is inclined to approach the outer surface of the casing as it goes from the exhaust gas inlet side of the exhaust gas inlet pipe toward the exhaust gas outlet side. According to claim 1,
Exhaust gas purification apparatus, characterized in that the exhaust gas inlet pipe is attached to the casing to cover the exhaust gas inlet. According to claim 1,
The exhaust gas inlet pipe, the exhaust gas purification apparatus, characterized in that the speech along the longitudinal direction of the casing. According to claim 1,
An exhaust gas purifying device, characterized in that a concave surface portion concave outward is formed on an inner surface side of the side end portion near the exhaust gas inlet in the casing. The method according to any one of claims 1 to 4,
A portion of the pipe wall of the exhaust gas inlet pipe near the exhaust gas outlet port is inclined to be separated from the center line of the exhaust gas inlet side toward the exhaust gas outlet side from the exhaust gas inlet side of the exhaust gas inlet pipe. Exhaust gas purification device.

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